It has been recognized that the flavor and aroma of coffee deteriorates or is adversely effected by oxidation. Oxidation can result from excessive exposure of the coffee to the atmosphere. It is also believed that the loss of vapors or steam from the liquid results in reduced flavor and aroma. This is particularly true in situations where a pot of coffee stands in a heated condition for a long period of time after brewing so that rather significant amounts of vapors or steam can escape from the pot.
This problem of coffee deterioration has been previously recognized in U.S. Pat. No. 3,974,758 to Stone (incorporated herein by reference). In that patent, a follower member is used to reduce the surface area of the coffee which is exposed to the atmosphere. It is also known in other patents to use various devices to inhibit the loss of vapors from a liquid or to limit the area of contact between a liquid and its surrounding atmosphere. See for example, U.S. Pat. Nos. 1,014,294; 1,714,482; 2,572,101 and 3,987,941 (all incorporated herein by reference).
Accordingly, heretofore a device which is effective for preserving the aroma and taste of coffee has not been known.